Consideration of selective and nonselective absorption by water vapor and ozone when sounding atmospheric organic aerosol with a CO2 laser based IR lidar

2021 ◽  
Vol 34 (11) ◽  
pp. 856-859
Author(s):  
A.V. Klimkin ◽  
G.P. Kokhanenko ◽  
T.E. Kuraeva ◽  
Yu.N. Ponomarev ◽  
I.V. Ptashnik
Keyword(s):  
Water Vapor ◽  
Organic Aerosol ◽  
Nonselective Absorption

Consideration of selective and nonselective absorption by water vapor and ozone when sounding atmospheric organic aerosol with a CO2 laser-based IR lidar

2021 ◽  
Author(s):  
Anton Klimkin ◽  
Grigorii Kokhanenko ◽  
Tatiana E. Kuraeva ◽  
Yurii Ponomarev ◽  
Igor Ptashnik
Keyword(s):  
Water Vapor ◽  
Co2 Laser ◽  
Organic Aerosol ◽  
Nonselective Absorption

Formation of Secondary Organic Aerosol by Reactive Condensation of Furandiones, Aldehydes, and Water Vapor onto Inorganic Aerosol Seed Particles

2004 ◽  
Vol 38 (19) ◽  
pp. 5064-5072 ◽  
Author(s):  
Charles A. Koehler ◽  
Jeremiah D. Fillo ◽  
Kyle A. Ries ◽  
José T. Sanchez ◽  
David O. De Haan
Keyword(s):  
Water Vapor ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Seed Particles ◽  
Inorganic Aerosol

scholarly journals Hygroscopicity of Polycatechol and Polyguaiacol Secondary Organic Aerosol in sub- and supersaturated water vapor environments

2022 ◽  
Author(s):  
Kotiba A Malek ◽  
Kanishk Gohil ◽  
Hind A. Al-Abadleh ◽  
Akua Asa-Awuku
Keyword(s):  
Water Vapor ◽  
Water Uptake ◽  
Biomass Burning ◽  
Aromatic Compounds ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Quantitative Information ◽  
Insoluble Particles ◽  
Catalyzed Reactions

Polycatechol and polyguaiacol are light-absorbing and water-insoluble particles that efficiently form from iron-catalyzed reactions with aromatic compounds from biomass burning emissions. Little quantitative information is known about their water uptake...

scholarly journals Impacts of water partitioning and polarity of organic compounds on secondary organic aerosol over eastern China

2020 ◽  
Vol 20 (12) ◽  
pp. 7291-7306
Author(s):  
Jingyi Li ◽  
Haowen Zhang ◽  
Qi Ying ◽  
Zhijun Wu ◽  
Yanli Zhang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Air Quality ◽  
Organic Compounds ◽  
Activity Coefficients ◽  
Secondary Organic Aerosol ◽  
Eastern China ◽  
Organic Aerosol ◽  
Water Mixture ◽  
Water Partitioning ◽  
The Yrd

Abstract. Secondary organic aerosol (SOA) is an important component of fine particular matter (PM2.5). Most air quality models use an equilibrium partitioning method along with the saturation vapor pressure (SVP) of semivolatile organic compounds (SVOCs) to predict SOA formation. However, the models typically assume that the organic particulate matter (OPM) is an ideal mixture and ignore the partitioning of water vapor to OPM. In this study, the Community Multiscale Air Quality model (CMAQ) is updated to investigate the impacts of water vapor partitioning and nonideality of the organic–water mixture on SOA formation during winter (January) and summer (July) of 2013 over eastern China. The updated model treats the partitioning of water vapor molecules into OPM and uses the universal functional activity coefficient (UNIFAC) model to estimate the activity coefficients of species in the organic–water mixture. The modified model can generally capture the observed surface organic carbon (OC) with a correlation coefficient R of 0.7 and the surface organic aerosol (OA) with the mean fractional bias (MFB) and mean fractional error (MFE) of −0.28 and 0.54, respectively. SOA concentration shows significant seasonal and spatial variations, with high concentrations in the North China Plain (NCP), central China, and the Sichuan Basin (SCB) regions during winter (up to 25 µg m−3) and in the Yangtze River Delta (YRD) during summer (up to 16 µg m−3). In winter, SOA decreases slightly in the updated model, with a monthly averaged relative change of 10 %–20 % in the highly concentrated areas, mainly due to organic–water interactions. The monthly averaged concentration of SOA increases greatly in summer, by 20 %–50 % at the surface and 30 %–60 % in the whole column. The increase in SOA is mainly due to the increase in biogenic SOA in inland areas and anthropogenic SOA in coastal areas. As a result, the averaged aerosol optical depth (AOD) is increased by up to 10 %, and the cooling effect of aerosol radiative forcing (ARF) is enhanced by up to 15 % over the YRD in summer. The aerosol liquid water content associated with OPM (ALWorg) at the surface is relatively high in inland areas in winter and over the ocean in summer, with a monthly averaged concentration of 0.5–3.0 and 5–7 µg m−3, respectively. The hygroscopicity parameter κ of OA based on the κ–Köhler theory is determined using the modeled ALWorg. The correlation of κ with the O:C ratio varies significantly across different cities and seasons. Analysis of two representative cities, Jinan (in the NCP) and Nanjing (in the YRD), shows that the impacts of water partitioning and nonideality of the organic–water mixture on SOA are sensitive to temperature, relative humidity (RH), and the SVP of SVOCs. The two processes exhibit opposite impacts on SOA in eastern China. Water uptake increases SOA by up to 80 % in the organic phase, while including nonunity activity coefficients decreases SOA by up to 50 %. Our results indicate that both water partitioning into OPM and the activity coefficients of the condensed organics should be considered in simulating SOA formation from gas–particle partitioning, especially in hot and humid environments.

scholarly journals Biomass-burning impact on CCN number, hygroscopicity and cloud formation during summertime in the eastern Mediterranean

2016 ◽  
Vol 16 (11) ◽  
pp. 7389-7409 ◽  
Author(s):  
Aikaterini Bougiatioti ◽  
Spiros Bezantakos ◽  
Iasonas Stavroulas ◽  
Nikos Kalivitis ◽  
Panagiotis Kokkalis ◽  
...  
Keyword(s):  
Water Vapor ◽  
Chemical Composition ◽  
Biomass Burning ◽  
Eastern Mediterranean ◽  
Bulk Composition ◽  
Cloud Droplet ◽  
Organic Aerosol ◽  
Particle Sizes ◽  
Hygroscopic Properties ◽  
The Impact

Abstract. This study investigates the concentration, cloud condensation nuclei (CCN) activity and hygroscopic properties of particles influenced by biomass burning in the eastern Mediterranean and their impacts on cloud droplet formation. Air masses sampled were subject to a range of atmospheric processing (several hours up to 3 days). Values of the hygroscopicity parameter, κ, were derived from CCN measurements and a Hygroscopic Tandem Differential Mobility Analyzer (HTDMA). An Aerosol Chemical Speciation Monitor (ACSM) was also used to determine the chemical composition and mass concentration of non-refractory components of the submicron aerosol fraction. During fire events, the increased organic content (and lower inorganic fraction) of the aerosol decreases the values of κ, for all particle sizes. Particle sizes smaller than 80 nm exhibited considerable chemical dispersion (where hygroscopicity varied up to 100 % for particles of same size); larger particles, however, exhibited considerably less dispersion owing to the effects of condensational growth and cloud processing. ACSM measurements indicate that the bulk composition reflects the hygroscopicity and chemical nature of the largest particles (having a diameter of  ∼  100 nm at dry conditions) sampled. Based on positive matrix factorization (PMF) analysis of the organic ACSM spectra, CCN concentrations follow a similar trend as the biomass-burning organic aerosol (BBOA) component, with the former being enhanced between 65 and 150 % (for supersaturations ranging between 0.2 and 0.7 %) with the arrival of the smoke plumes. Using multilinear regression of the PMF factors (BBOA, OOA-BB and OOA) and the observed hygroscopicity parameter, the inferred hygroscopicity of the oxygenated organic aerosol components is determined. We find that the transformation of freshly emitted biomass burning (BBOA) to more oxidized organic aerosol (OOA-BB) can result in a 2-fold increase of the inferred organic hygroscopicity; about 10 % of the total aerosol hygroscopicity is related to the two biomass-burning components (BBOA and OOA-BB), which in turn contribute almost 35 % to the fine-particle organic water of the aerosol. Observation-derived calculations of the cloud droplet concentrations that develop for typical boundary layer cloud conditions suggest that biomass burning increases droplet number, on average by 8.5 %. The strongly sublinear response of clouds to biomass-burning (BB) influences is a result of strong competition of CCN for water vapor, which results in very low maximum supersaturation (0.08 % on average). Attributing droplet number variations to the total aerosol number and the chemical composition variations shows that the importance of chemical composition increases with distance, contributing up to 25 % of the total droplet variability. Therefore, although BB may strongly elevate CCN numbers, the impact on droplet number is limited by water vapor availability and depends on the aerosol particle concentration levels associated with the background.

New Design for a Differentially Pumped Hydration Chamber for a Siemens IA

1971 ◽  
Vol 29 ◽  
pp. 44-45
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscopy ◽  
Water Vapor ◽  
Electron Diffraction ◽  
Water Vapor Pressure ◽  
Biological Materials ◽  
Thin Membrane ◽  
Reliable System ◽  
System A ◽  
Water Films ◽  
Aperture Opening

Electron microscopy and diffraction of biological materials in the hydrated state requires the construction of a chamber in which the water vapor pressure can be maintained at saturation for a given specimen temperature, while minimally affecting the normal vacuum of the remainder of the microscope column. Initial studies with chambers closed by thin membrane windows showed that at the film thicknesses required for electron diffraction at 100 KV the window failure rate was too high to give a reliable system. A single stage, differentially pumped specimen hydration chamber was constructed, consisting of two apertures (70-100μ), which eliminated the necessity of thin membrane windows. This system was used to obtain electron diffraction and electron microscopy of water droplets and thin water films. However, a period of dehydration occurred during initial pumping of the microscope column. Although rehydration occurred within five minutes, biological materials were irreversibly damaged. Another limitation of this system was that the specimen grid was clamped between the apertures, thus limiting the yield of view to the aperture opening.

Hydration Chamber for Jeolco 200 Kv Microscope

1970 ◽  
Vol 28 ◽  
pp. 542-543
Author(s):  
V. R. Matricardi ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscope ◽  
Water Vapor ◽  
Vapor Pressure ◽  
Pressure Gradient ◽  
Room Temperature ◽  
List Type ◽  
Type Number ◽  
Equilibrium Vapor Pressure

In order to observe room temperature hydrated specimens in an electron microscope, the following conditions should be satisfied: The specimen should be surrounded by water vapor as close as possible to the equilibrium vapor pressure corresponding to the temperature of the specimen.The specimen grid should be inserted, focused and photo graphed in the shortest possible time in order to minimize dehydration.The full area of the specimen grid should be visible in order to minimize the number of changes of specimen required.There should be no pressure gradient across the grid so that specimens can be straddled across holes.Leakage of water vapor to the column should be minimized.

Warm and freeze-fracture of cotton seed radicles

1987 ◽  
Vol 45 ◽  
pp. 984-985
Author(s):  
E. L. Vigil ◽  
E. F. Erbe
Keyword(s):  
Thin Film ◽  
Water Vapor ◽  
Fracture Surface ◽  
Membrane Structure ◽  
Room Temperature ◽  
Freeze Fracture ◽  
Longitudinal Axis ◽  
Fracture Plane ◽  
Cotton Seeds ◽  
Condensed Water

In cotton seeds the radicle has 12% moisture content which makes it possible to prepare freeze-fracture replicas without fixation or cryoprotection. For this study we have examined replicas of unfixed radicle tissue fractured at room temperature to obtain data on organelle and membrane structure.Excised radicles from seeds of cotton (Gossyplum hirsutum L. M-8) were fractured at room temperature along the longitudinal axis. The fracture was initiated by spliting the basal end of the excised radicle with a razor. This procedure produced a fracture through the tissue along an unknown fracture plane. The warm fractured radicle halves were placed on a thin film of 100% glycerol on a flat brass cap with fracture surface up. The cap was rapidly plunged into liquid nitrogen and transferred to a freeze- etch unit. The sample was etched for 3 min at -95°C to remove any condensed water vapor and then cooled to -150°C for platinum/carbon evaporation.

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